Group reporting of user equipment measurements in multi-round trip time positioning

ABSTRACT

Disclosed are techniques for group reporting of UE receive-transmit (Rx-Tx) time difference measurements for multi-RTT positioning. A plurality of downlink reference signals (DL RSs) are received from a plurality of transmission reception points (TRPs). A corresponding plurality of uplink reference signals (UL RSs) are transmitted to the plurality of TRPs. One or more numerology factors are determined for the plurality of TRPs. A measurement report is generated for the plurality of TRPs based on the numerology factors. The measurement report is transmitted to a network entity. The measurement report includes UE receive-transmit (Rx-Tx) time difference measurements for at least two of the TRPs.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application for Patent is a continuation of U.S. patentapplication Ser. No. 16/738,988, entitled “GROUP REPORTING OF USEREQUIPMENT MEASUREMENTS IN MULTI-ROUND TRIP TIME POSITIONING,” filed Jan.9, 2020, which claims priority to Greek Patent Application No.20190100025, entitled “GROUP REPORTING OF UE RX-TX MEASUREMENTS INMULTI-RTT POSITIONING,” filed Jan. 11, 2019, each of which is assignedto the assignee hereof, and expressly incorporated herein by referencein its entirety.

INTRODUCTION 1. Technical Field

Various aspects described herein generally relate to wirelesscommunication systems, and more particularly, to group reporting of userequipment (UE) Rx-Tx measurements in multi-round trip time (RTT)positioning in wireless networks.

2. Background

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service and a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax). There are presentlymany different types of wireless communication systems in use, includingcellular and personal communications service (PCS) systems. Examples ofknown cellular systems include the cellular analog advanced mobile phonesystem (AMPS), and digital cellular systems based on code divisionmultiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), the Global System for Mobile access(GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard, referred to as New Radio (NR),calls for higher data transfer speeds, greater numbers of connections,and better coverage, among other improvements. The 5G standard,according to the Next Generation Mobile Networks Alliance, is designedto provide data rates of several tens of megabits per second to each oftens of thousands of users, with 1 gigabit per second to tens of workerson an office floor. Several hundreds of thousands of simultaneousconnections should be supported in order to support large sensordeployments. Consequently, the spectral efficiency of 5G mobilecommunications should be significantly enhanced compared to the current4G standard. Furthermore, signaling efficiencies should be enhanced andlatency should be substantially reduced compared to current standards.

Some wireless communication networks, such as 5G, support operation atvery high and even extremely-high frequency (EHF) bands, such asmillimeter wave (mmW) frequency bands (generally, wavelengths of 1 mm to10 mm, or 30 to 300 GHz). These extremely high frequencies may supportvery high throughput such as up to six gigabits per second (Gbps).

To support position estimations in terrestrial wireless networks, amobile device can be configured to measure and report the observed timedifference of arrival (OTDOA) or reference signal timing difference(RSTD) between reference RF signals received from two or more networknodes (e.g., different base stations or different transmission points(e.g., antennas) belonging to the same base station). The mobile devicecan also be configured to report the time of arrival (ToA) of RFsignals.

With OTDOA, when the mobile device reports the time difference ofarrival (TDOA) between RF signals from two network nodes, the locationof the mobile device is then known to lie on a hyperbola with thelocations of the two network nodes as the foci. Measuring TDOAs betweenmultiple pairs of network nodes allows for solving for the mobiledevice's position as intersections of the hyperbolas.

Round trip time (RTT) is another technique for determining a position ofa mobile device. RTT is a two-way messaging technique (network node tomobile device and mobile device to network node), with both the mobiledevice and the network node reporting their receive-to-transmit (Rx-Tx)time differences to a positioning entity, such as a location server orlocation management function (LMF), that computes the mobile device'sposition. This allows for computing the back-and-forth flight timebetween the mobile device and the network node. The location of themobile device is then known to lie on a circle with a center at thenetwork node's position. Reporting RTTs with multiple network nodesallows the positioning entity to solve for the mobile device's positionas the intersections of the circles.

SUMMARY

This summary identifies features of some example aspects, and is not anexclusive or exhaustive description of the disclosed subject matter.Whether features or aspects are included in, or omitted from thissummary is not intended as indicative of relative importance of suchfeatures. Additional features and aspects are described, and will becomeapparent to persons skilled in the art upon reading the followingdetailed description and viewing the drawings that form a part thereof.

In accordance with the various aspects disclosed herein, at least oneaspect includes, a method performed by a user equipment (UE), the methodincluding: receiving a plurality of downlink reference signals (DL RSs)from a plurality of TRPs; transmitting a corresponding plurality ofuplink reference signals (UL RSs) to the plurality of TRPs; determiningone or more numerology factors for the plurality of TRPs; generating ameasurement report for the plurality of TRPs based on the numerologyfactors; and transmitting the measurement report to a network entity,where the measurement report includes a receive-transmit (Rx-Tx) timedifference for at least two of the TRPs.

In accordance with the various aspects disclosed herein, at least oneaspect includes, a user equipment (UE) including: a transceiver; and aprocessor coupled to the memory and the transceiver, where thetransceiver, the memory in combination with the processor are configuredto: receive a plurality of downlink reference signals (DL RSs) from aplurality of TRPs; transmit a corresponding plurality of uplinkreference signals (UL RSs) to the plurality of TRPs; determine one ormore numerology factors for the plurality of TRPs; generate ameasurement report for the plurality of TRPs based on the numerologyfactors; and transmit the measurement report to a network entity, wherethe measurement report includes a receive-transmit (Rx-Tx) timedifference for at least two of the TRPs.

In accordance with the various aspects disclosed herein, at least oneaspect includes, a method performed by a network entity, the methodincluding: receiving, from a user equipment (UE) a measurement report ofa plurality of TRPs; and determining a position of the UE based on themeasurement report, and/or forwarding the measurement report to alocation server, where the measurement report includes areceive-transmit (Rx-Tx) time difference for at least two of the TRPs,and where the Rx-Tx time difference for each TRP is determined based onnumerology factors of communications between the plurality of TRPs andthe UE.

In accordance with the various aspects disclosed herein, at least oneaspect includes, a network entity including: a communication device; anda processor coupled to the memory and the communication device, wherethe communication device, the memory in combination with the processorare configured to: receive, from a user equipment (UE) a measurementreport of a plurality of TRPs; and determine a position of the UE basedon the measurement report, and/or forwarding the measurement report to alocation server, where the measurement report includes areceive-transmit (Rx-Tx) time difference for at least two of the TRPs,and where the Rx-Tx time difference for each TRP is determined based onnumerology factors of communications between the plurality of TRPs andthe UE.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description ofexamples of one or more aspects of the disclosed subject matter and areprovided solely for illustration of the examples and not limitationthereof:

FIG. 1 illustrates an exemplary wireless communications system inaccordance with one or more aspects of the disclosure;

FIGS. 2A and 2B illustrate example wireless network structures inaccordance with one or more aspects of the disclosure;

FIGS. 3A to 3C are simplified block diagrams of several sample aspectsof components that may be employed in wireless communication nodes andconfigured to support communication in accordance with one or moreaspects of the disclosure;

FIG. 4 illustrates a scenario for determining a position of a UE througha multi-RTT procedure in accordance with one or more aspects of thedisclosure;

FIG. 5 illustrates a diagram of exemplary timings for determining an RTTbetween a serving transmission reception point (TRP) and a UE inaccordance with one or more aspects of the disclosure;

FIG. 6 illustrates a scenario in which measurement reports for multipleTRPs are reported by the UE;

FIG. 7 illustrates an exemplary method performed by a UE for measurementreporting in accordance with an aspect of the disclosure;

FIG. 8 illustrates an example process performed by a UE to group theTRPs in the measurement report;

FIG. 9 illustrates an exemplary method performed a serving TRP formeasurement reporting in accordance with an aspect of the disclosure;

FIGS. 10 and 11 are other simplified block diagrams of several sampleaspects of apparatuses configured to support positioning andcommunication as taught herein.

DETAILED DESCRIPTION

Aspects of the disclosure are provided in the following description andrelated drawings directed to various examples provided for illustrationpurposes. Alternate aspects may be devised without departing from thescope of the disclosure. Additionally, well-known elements of thedisclosure will not be described in detail or will be omitted so as notto obscure the relevant details of the disclosure.

The words “exemplary” and/or “example” are used herein to mean “servingas an example, instance, or illustration.” Any aspect described hereinas “exemplary” and/or “example” is not necessarily to be construed aspreferred or advantageous over other aspects. Likewise, the term“aspects of the disclosure” does not require that all aspects of thedisclosure include the discussed feature, advantage or mode ofoperation.

Those of skill in the art will appreciate that the information andsignals described below may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the description below may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof, depending inpart on the particular application, in part on the desired design, inpart on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions tobe performed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits (e.g., application specific integrated circuits(ASICs)), by program instructions being executed by one or moreprocessors, or by a combination of both. Additionally, the sequence(s)of actions described herein can be considered to be embodied entirelywithin any form of non-transitory computer-readable storage mediumhaving stored therein a corresponding set of computer instructions that,upon execution, would cause or instruct an associated processor of adevice to perform the functionality described herein. Thus, the variousaspects of the disclosure may be embodied in a number of differentforms, all of which have been contemplated to be within the scope of theclaimed subject matter. In addition, for each of the aspects describedherein, the corresponding form of any such aspects may be describedherein as, for example, “logic configured to” perform the describedaction.

As used herein, the terms “user equipment” (UE) and “base station” arenot intended to be specific or otherwise limited to any particular radioaccess technology (RAT), unless otherwise noted. In general, a UE may beany device (e.g., a mobile phone, router, tablet computer, laptopcomputer, tracking device, wearable (e.g., smartwatch, glasses,augmented reality (AR)/virtual reality (VR) headset, etc.), vehicle(e.g., automobile, motorcycle, bicycle, etc.), Internet of Things (IoT)device, etc.) used by a user to communicate over a wirelesscommunications network. A UE may be mobile or may (e.g., at certaintimes) be stationary, and may communicate with a radio access network(RAN). As used herein, the term “UE” may be referred to interchangeablyas an “access terminal” or “AT,” a “client device,” a “wireless device,”a “subscriber device,” a “subscriber terminal,” a “subscriber station,”a “user terminal” or UT, a “mobile terminal,” a “mobile station,” orvariations thereof. Generally, UEs can communicate with a core networkvia a RAN, and through the core network the UEs can be connected withexternal networks such as the Internet and with other UEs. Of course,other mechanisms of connecting to the core network and/or the Internetare also possible for the UEs, such as over wired access networks,wireless local area network (WLAN) networks (e.g., based on IEEE 802.11,etc.) and so on.

A base station may operate according to one of several RATs incommunication with UEs depending on the network in which it is deployed,and may be alternatively referred to as an access point (AP), a networknode, a NodeB, an evolved NodeB (eNB), a New Radio (NR) Node B (alsoreferred to as a gNB or gNodeB), etc. In addition, in some systems abase station may provide purely edge node signaling functions while inother systems it may provide additional control and/or networkmanagement functions. A communication link through which UEs can sendsignals to a base station is called an uplink (UL) channel (e.g., areverse traffic channel, a reverse control channel, an access channel,etc.). A communication link through which the base station can sendsignals to UEs is called a downlink (DL) or forward link channel (e.g.,a paging channel, a control channel, a broadcast channel, a forwardtraffic channel, etc.). As used herein the term traffic channel (TCH)can refer to either an UL/reverse or DL/forward traffic channel.

The term “base station” may refer to a single physicaltransmission-reception point (TRP) or to multiple physical TRPs that mayor may not be co-located. For example, where the term “base station”refers to a single physical TRP, the physical TRP may be an antenna ofthe base station corresponding to a cell of the base station. Where theterm “base station” refers to multiple co-located physical TRPs, thephysical TRPs may be an array of antennas (e.g., as in a multiple-inputmultiple-output (MIMO) system or where the base station employsbeamforming) of the base station. Where the term “base station” refersto multiple non-co-located physical TRPs, the physical TRPs may be adistributed antenna system (DAS) (a network of spatially separatedantennas connected to a common source via a transport medium) or aremote radio head (RRH) (a remote base station connected to a servingbase station). Alternatively, the non-co-located physical TRPs may bethe serving base station receiving the measurement report from the UEand a neighbor base station whose reference RF signals the UE ismeasuring. Because a TRP is the point from which a base stationtransmits and receives wireless signals, as used herein, references totransmission from or reception at a base station are to be understood asreferring to a particular TRP of the base station.

An “RF signal” comprises an electromagnetic wave of a given frequencythat transports information through the space between a transmitter anda receiver. As used herein, a transmitter may transmit a single “RFsignal” or multiple “RF signals” to a receiver. However, the receivermay receive multiple “RF signals” corresponding to each transmitted RFsignal due to the propagation characteristics of RF signals throughmultipath channels. The same transmitted RF signal on different pathsbetween the transmitter and receiver may be referred to as a “multipath”RF signal.

According to various aspects, FIG. 1 illustrates an exemplary wirelesscommunications system 100. The wireless communications system 100 (whichmay also be referred to as a wireless wide area network (WWAN)) mayinclude various base stations 102 and various UEs 104. The base stations102 may include macro cell base stations (high power cellular basestations) and/or small cell base stations (low power cellular basestations). In an aspect, the macro cell base station may include eNBswhere the wireless communications system 100 corresponds to an LTEnetwork, or gNBs where the wireless communications system 100corresponds to a NR network, or a combination of both, and the smallcell base stations may include femtocells, picocells, microcells, etc.

The base stations 102 may collectively form a RAN and interface with acore network 170 (e.g., an evolved packet core (EPC) or next generationcore (NGC)) through backhaul links 122, and through the core network 170to one or more location servers 172. In addition to other functions, thebase stations 102 may perform functions that relate to one or more oftransferring user data, radio channel ciphering and deciphering,integrity protection, header compression, mobility control functions(e.g., handover, dual connectivity), inter-cell interferencecoordination, connection setup and release, load balancing, distributionfor non-access stratum (NAS) messages, NAS node selection,synchronization, RAN sharing, multimedia broadcast multicast service(MBMS), subscriber and equipment trace, RAN information management(RIM), paging, positioning, and delivery of warning messages. The basestations 102 may communicate with each other directly or indirectly(e.g., through the EPC/NGC) over backhaul links 134, which may be wiredor wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. In an aspect, one or more cellsmay be supported by a base station 102 in each coverage area 110. A“cell” is a logical communication entity used for communication with abase station (e.g., over some frequency resource, referred to as acarrier frequency, component carrier, carrier, band, or the like), andmay be associated with an identifier (e.g., a physical cell identifier(PCI), a virtual cell identifier (VCI)) for distinguishing cellsoperating via the same or a different carrier frequency. In some cases,different cells may be configured according to different protocol types(e.g., machine-type communication (MTC), narrowband IoT (NB-IoT),enhanced mobile broadband (eMBB), or others) that may provide access fordifferent types of UEs. Because a cell is supported by a specific basestation, the term “cell” may refer to either or both the logicalcommunication entity and the base station that supports it, depending onthe context. In some cases, the term “cell” may also refer to ageographic coverage area of a base station (e.g., a sector), insofar asa carrier frequency can be detected and used for communication withinsome portion of geographic coverage areas 110.

While neighboring macro cell base station 102 geographic coverage areas110 may partially overlap (e.g., in a handover region), some of thegeographic coverage areas 110 may be substantially overlapped by alarger geographic coverage area 110. For example, a small cell basestation 102′ may have a coverage area 110′ that substantially overlapswith the coverage area 110 of one or more macro cell base stations 102.A network that includes both small cell and macro cell base stations maybe known as a heterogeneous network. A heterogeneous network may alsoinclude home eNBs (HeNBs), which may provide service to a restrictedgroup known as a closed subscriber group (CSG).

The communication links 120 between the base stations 102 and the UEs104 may include UL (also referred to as reverse link) transmissions froma UE 104 to a base station 102 and/or downlink (DL) (also referred to asforward link) transmissions from a base station 102 to a UE 104. Thecommunication links 120 may use MIMO antenna technology, includingspatial multiplexing, beamforming, and/or transmit diversity. Thecommunication links 120 may be through one or more carrier frequencies.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL).

The wireless communications system 100 may further include a wirelesslocal area network (WLAN) access point (AP) 150 in communication withWLAN stations (STAs) 152 via communication links 154 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may performa clear channel assessment (CCA) or listen before talk (LBT) procedureprior to communicating in order to determine whether the channel isavailable.

The small cell base station 102′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 102′ may employ LTE or NRtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 150. The small cell base station 102′, employing LTE/5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. NR in unlicensed spectrum maybe referred to as NR-U. LTE in an unlicensed spectrum may be referred toas LTE-U, licensed assisted access (LAA), or MulteFire.

The wireless communications system 100 may further include a millimeterwave (mmW) base station 180 that may operate in mmW frequencies and/ornear mmW frequencies in communication with a UE 182. Extremely highfrequency (EHF) is part of the RF in the electromagnetic spectrum. EHFhas a range of 30 GHz to 300 GHz and a wavelength between 1 millimeterand 10 millimeters. Radio waves in this band may be referred to as amillimeter wave. Near mmW may extend down to a frequency of 3 GHz with awavelength of 100 millimeters. The super high frequency (SHF) bandextends between 3 GHz and 30 GHz, also referred to as centimeter wave.Communications using the mmW/near mmW radio frequency band have highpath loss and a relatively short range. The mmW base station 180 and theUE 182 may utilize beamforming (transmit and/or receive) over a mmWcommunication link 184 to compensate for the extremely high path lossand short range. Further, it will be appreciated that in alternativeconfigurations, one or more base stations 102 may also transmit usingmmW or near mmW and beamforming. Accordingly, it will be appreciatedthat the foregoing illustrations are merely examples and should not beconstrued to limit the various aspects disclosed herein.

Transmit beamforming is a technique for focusing an RF signal in aspecific direction. Traditionally, when a network node (e.g., a basestation) broadcasts an RF signal, it broadcasts the signal in alldirections (omni-directionally). With transmit beamforming, the networknode determines where a given target device (e.g., a UE) is located(relative to the transmitting network node) and projects a strongerdownlink RF signal in that specific direction, thereby providing afaster (in terms of data rate) and stronger RF signal for the receivingdevice(s). To change the directionality of the RF signal whentransmitting, a network node can control the phase and relativeamplitude of the RF signal at each of the one or more transmitters thatare broadcasting the RF signal. For example, a network node may use anarray of antennas (referred to as a “phased array” or an “antennaarray”) that creates a beam of RF waves that can be “steered” to pointin different directions, without actually moving the antennas.Specifically, the RF current from the transmitter is fed to theindividual antennas with the correct phase relationship so that theradio waves from the separate antennas add together to increase theradiation in a desired direction, while cancelling to suppress radiationin undesired directions.

Transmit beams may be quasi-collocated, meaning that they appear to thereceiver (e.g., a UE) as having the same parameters, regardless ofwhether or not the transmitting antennas of the network node themselvesare physically collocated. In NR, there are four types ofquasi-collocation (QCL) relations. Specifically, a QCL relation of agiven type means that certain parameters about a second reference RFsignal on a second beam can be derived from information about a sourcereference RF signal on a source beam. Thus, if the source reference RFsignal is QCL Type A, the receiver can use the source reference RFsignal to estimate the Doppler shift, Doppler spread, average delay, anddelay spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type B, the receivercan use the source reference RF signal to estimate the Doppler shift andDoppler spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type C, the receivercan use the source reference RF signal to estimate the Doppler shift andaverage delay of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type D, the receivercan use the source reference RF signal to estimate the spatial receiveparameter of a second reference RF signal transmitted on the samechannel.

In receive beamforming, the receiver uses a receive beam to amplify RFsignals detected on a given channel. For example, the receiver canincrease the gain setting and/or adjust the phase setting of an array ofantennas in a particular direction to amplify (e.g., to increase thegain level of) the RF signals received from that direction. Thus, when areceiver is said to beamform in a certain direction, it means the beamgain in that direction is high relative to the beam gain along otherdirections, or the beam gain in that direction is the highest comparedto the beam gain in that direction of all other receive beams availableto the receiver. This results in a stronger received signal strength(e.g., reference signal received power (RSRP), reference signal receivedquality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) ofthe RF signals received from that direction.

Receive beams may be spatially related. A spatial relation means thatparameters for a transmit beam for a second reference signal can bederived from information about a receive beam for a first referencesignal. For example, a UE may use a particular receive beam to receive areference downlink reference signal (e.g., synchronization signal block(SSB)) from a base station. The UE can then form a transmit beam forsending an uplink reference signal (e.g., sounding reference signal(SRS)) to that base station based on the parameters of the receive beam.

Note that a “downlink” beam may be either a transmit beam or a receivebeam, depending on the entity forming it. For example, if a base stationis forming the downlink beam to transmit a reference signal to a UE, thedownlink beam is a transmit beam. If the UE is forming the downlinkbeam, however, it is a receive beam to receive the downlink referencesignal. Similarly, an “uplink” beam may be either a transmit beam or areceive beam, depending on the entity forming it. For example, if a basestation is forming the uplink beam, it is an uplink receive beam, and ifa UE is forming the uplink beam, it is an uplink transmit beam.

In 5G, the frequency spectrum in which wireless nodes (e.g., basestations 102/180, UEs 104/182) operate is divided into multiplefrequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In amulti-carrier system, such as 5G, one of the carrier frequencies isreferred to as the “primary carrier” or “anchor carrier” or “primaryserving cell” or “PCell,” and the remaining carrier frequencies arereferred to as “secondary carriers” or “secondary serving cells” or“SCells.” In carrier aggregation, the anchor carrier is the carrieroperating on the primary frequency (e.g., FR1) utilized by a UE 104/182and the cell in which the UE 104/182 either performs the initial radioresource control (RRC) connection establishment procedure or initiatesthe RRC connection re-establishment procedure. The primary carriercarries all common and UE-specific control channels, and may be acarrier in a licensed frequency (however, this is not always the case).A secondary carrier is a carrier operating on a second frequency (e.g.,FR2) that may be configured once the RRC connection is establishedbetween the UE 104 and the anchor carrier and that may be used toprovide additional radio resources. In some cases, the secondary carriermay be a carrier in an unlicensed frequency. The secondary carrier maycontain only necessary signaling information and signals, for example,those that are UE-specific may not be present in the secondary carrier,since both primary uplink and downlink carriers are typicallyUE-specific. This means that different UEs 104/182 in a cell may havedifferent downlink primary carriers. The same is true for the uplinkprimary carriers. The network is able to change the primary carrier ofany UE 104/182 at any time. This is done, for example, to balance theload on different carriers. Because a “serving cell” (whether a PCell oran SCell) corresponds to a carrier frequency/component carrier overwhich some base station is communicating, the term “cell,” “servingcell,” “component carrier,” “carrier frequency,” and the like can beused interchangeably.

For example, still referring to FIG. 1 , one of the frequencies utilizedby the macro cell base stations 102 may be an anchor carrier (or“PCell”) and other frequencies utilized by the macro cell base stations102 and/or the mmW base station 180 may be secondary carriers(“SCells”). The simultaneous transmission and/or reception of multiplecarriers enables the UE 104/182 to significantly increase its datatransmission and/or reception rates. For example, two 20 MHz aggregatedcarriers in a multi-carrier system would theoretically lead to atwo-fold increase in data rate (i.e., 40 MHz), compared to that attainedby a single 20 MHz carrier.

The wireless communications system 100 may further include one or moreUEs, such as UE 190, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. In the example of FIG. 1 , UE 190 has a D2DP2P link 192 with one of the UEs 104 connected to one of the basestations 102 (e.g., through which UE 190 may indirectly obtain cellularconnectivity) and a D2D P2P link 194 with WLAN STA 152 connected to theWLAN AP 150 (through which UE 190 may indirectly obtain WLAN-basedInternet connectivity). In an example, the D2D P2P links 192 and 194 maybe supported with any well-known D2D RAT, such as LTE Direct (LTE-D),WiFi Direct (WiFi-D), Bluetooth®, and so on.

The wireless communications system 100 may further include a UE 164 thatmay communicate with a macro cell base station 102 over a communicationlink 120 and/or the mmW base station 180 over a mmW communication link184. For example, the macro cell base station 102 may support a PCelland one or more SCells for the UE 164 and the mmW base station 180 maysupport one or more SCells for the UE 164.

According to various aspects, FIG. 2A illustrates an example wirelessnetwork structure 200. For example, an NGC 210 (also referred to as a“5GC”) can be viewed functionally as control plane functions 214 (e.g.,UE registration, authentication, network access, gateway selection,etc.) and user plane functions 212, (e.g., UE gateway function, accessto data networks, IP routing, etc.) which operate cooperatively to formthe core network. User plane interface (NG-U) 213 and control planeinterface (NG-C) 215 connect the gNB 222 to the NGC 210 and specificallyto the control plane functions 214 and user plane functions 212. In anadditional configuration, an eNB 224 may also be connected to the NGC210 via NG-C 215 to the control plane functions 214 and NG-U 213 to userplane functions 212. Further, eNB 224 may directly communicate with gNB222 via a backhaul connection 223. In some configurations, the New RAN220 may only have one or more gNBs 222, while other configurationsinclude one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB224 may communicate with UEs 204 (e.g., any of the UEs depicted in FIG.1 ). Another optional aspect may include location server 230, which maybe in communication with the NGC 210 to provide location assistance forUEs 204. The location server 230 can be implemented as a plurality ofseparate servers (e.g., physically separate servers, different softwaremodules on a single server, different software modules spread acrossmultiple physical servers, etc.), or alternately may each correspond toa single server. The location server 230 can be configured to supportone or more location services for UEs 204 that can connect to thelocation server 230 via the core network, NGC 210, and/or via theInternet (not illustrated). Further, the location server 230 may beintegrated into a component of the core network, or alternatively may beexternal to the core network.

According to various aspects, FIG. 2B illustrates another examplewireless network structure 250. For example, an NGC 260 (also referredto as a “5GC”) can be viewed functionally as control plane functions,provided by an access and mobility management function (AMF)/user planefunction (UPF) 264, and user plane functions, provided by a sessionmanagement function (SMF) 262, which operate cooperatively to form thecore network (i.e., NGC 260). User plane interface 263 and control planeinterface 265 connect the eNB 224 to the NGC 260 and specifically to SMF262 and AMF/UPF 264, respectively. In an additional configuration, a gNB222 may also be connected to the NGC 260 via control plane interface 265to AMF/UPF 264 and user plane interface 263 to SMF 262. Further, eNB 224may directly communicate with gNB 222 via the backhaul connection 223,with or without gNB direct connectivity to the NGC 260. In someconfigurations, the New RAN 220 may only have one or more gNBs 222,while other configurations include one or more of both eNBs 224 and gNBs222. Either gNB 222 or eNB 224 may communicate with UEs 204 (e.g., anyof the UEs depicted in FIG. 1 ). The base stations of the New RAN 220communicate with the AMF-side of the AMF/UPF 264 over the N2 interfaceand the UPF-side of the AMF/UPF 264 over the N3 interface.

The functions of the AMF include registration management, connectionmanagement, reachability management, mobility management, lawfulinterception, transport for session management (SM) messages between theUE 204 and the SMF 262, transparent proxy services for routing SMmessages, access authentication and access authorization, transport forshort message service (SMS) messages between the UE 204 and the shortmessage service function (SMSF) (not shown), and security anchorfunctionality (SEAF). The AMF also interacts with the authenticationserver function (AUSF) (not shown) and the UE 204, and receives theintermediate key that was established as a result of the UE 204authentication process. In the case of authentication based on a UMTS(universal mobile telecommunications system) subscriber identity module(USIM), the AMF retrieves the security material from the AUSF. Thefunctions of the AMF also include security context management (SCM). TheSCM receives a key from the SEAF that it uses to derive access-networkspecific keys. The functionality of the AMF also includes locationservices management for regulatory services, transport for locationservices messages between the UE 204 and the location managementfunction (LMF) 270, as well as between the New RAN 220 and the LMF 270,evolved packet system (EPS) bearer identifier allocation forinterworking with the EPS, and UE 204 mobility event notification. Inaddition, the AMF also supports functionalities for non-3GPP accessnetworks.

Functions of the UPF include acting as an anchor point forintra-/inter-RAT mobility (when applicable), acting as an externalprotocol data unit (PDU) session point of interconnect to the datanetwork (not shown), providing packet routing and forwarding, packetinspection, user plane policy rule enforcement (e.g., gating,redirection, traffic steering), lawful interception (user planecollection), traffic usage reporting, quality of service (QoS) handlingfor the user plane (e.g., UL/DL rate enforcement, reflective QoS markingin the DL), UL traffic verification (service data flow (SDF) to QoS flowmapping), transport level packet marking in the UL and DL, DL packetbuffering and DL data notification triggering, and sending andforwarding of one or more “end markers” to the source RAN node.

The functions of the SMF 262 include session management, UE Internetprotocol (IP) address allocation and management, selection and controlof user plane functions, configuration of traffic steering at the UPF toroute traffic to the proper destination, control of part of policyenforcement and QoS, and downlink data notification. The interface overwhich the SMF 262 communicates with the AMF-side of the AMF/UPF 264 isreferred to as the N11 interface.

Another optional aspect may include a LMF 270, which may be incommunication with the NGC 260 to provide location assistance for UEs204. The LMF 270 can be implemented as a plurality of separate servers(e.g., physically separate servers, different software modules on asingle server, different software modules spread across multiplephysical servers, etc.), or alternately may each correspond to a singleserver. The LMF 270 can be configured to support one or more locationservices for UEs 204 that can connect to the LMF 270 via the corenetwork, NGC 260, and/or via the Internet (not illustrated).

FIGS. 3A, 3B, and 3C illustrate several sample components (representedby corresponding blocks) that may be incorporated into a UE 302 (whichmay correspond to any of the UEs described herein), a TRP 304 (which maycorrespond to any of the base stations, gNBs, eNBs, cells, etc.described herein), and a network node 306 (which may correspond to orembody any of the network functions described herein, including thelocation server 230 and the LMF 270) to support the file transmissionoperations as taught herein. It will be appreciated that thesecomponents may be implemented in different types of apparatuses indifferent implementations (e.g., in an ASIC, in a system-on-chip (SoC),etc.). The illustrated components may also be incorporated into otherapparatuses in a communication system. For example, other apparatuses ina system may include components similar to those described to providesimilar functionality. Also, a given apparatus may contain one or moreof the components. For example, an apparatus may include multipletransceiver components that enable the apparatus to operate on multiplecarriers and/or communicate via different technologies.

The UE 302 and the TRP 304 each include wireless wide area network(WWAN) transceiver 310 and 350, respectively, configured to communicatevia one or more wireless communication networks (not shown), such as anNR network, an LTE network, a GSM network, and/or the like. The WWANtransceivers 310 and 350 may be connected to one or more antennas 316and 356, respectively, for communicating with other network nodes, suchas other UEs, access points, base stations (e.g., eNBs, gNBs), etc., viaat least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wirelesscommunication medium of interest (e.g., some set of time/frequencyresources in a particular frequency spectrum). The WWAN transceivers 310and 350 may be variously configured for transmitting and encodingsignals 318 and 358 (e.g., messages, indications, information, and soon), respectively, and, conversely, for receiving and decoding signals318 and 358 (e.g., messages, indications, information, pilots, and soon), respectively, in accordance with the designated RAT. Specifically,the transceivers 310 and 350 include one or more transmitters 314 and354, respectively, for transmitting and encoding signals 318 and 358,respectively, and one or more receivers 312 and 352, respectively, forreceiving and decoding signals 318 and 358, respectively.

The UE 302 and the TRP 304 also include, at least in some cases,wireless local area network (WLAN) transceivers 320 and 360,respectively. The WLAN transceivers 320 and 360 may be connected to oneor more antennas 326 and 366, respectively, for communicating with othernetwork nodes, such as other UEs, access points, base stations, etc.,via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, etc.)over a wireless communication medium of interest. The WLAN transceivers320 and 360 may be variously configured for transmitting and encodingsignals 328 and 368 (e.g., messages, indications, information, and soon), respectively, and, conversely, for receiving and decoding signals328 and 368 (e.g., messages, indications, information, pilots, and soon), respectively, in accordance with the designated RAT. Specifically,the transceivers 320 and 360 include one or more transmitters 324 and364, respectively, for transmitting and encoding signals 328 and 368,respectively, and one or more receivers 322 and 362, respectively, forreceiving and decoding signals 328 and 368, respectively.

Transceiver circuitry including a transmitter and a receiver maycomprise an integrated device (e.g., embodied as a transmitter circuitand a receiver circuit of a single communication device) in someimplementations, may comprise a separate transmitter device and aseparate receiver device in some implementations, or may be embodied inother ways in other implementations. In an aspect, a transmitter mayinclude or be coupled to a plurality of antennas (e.g., antennas 316,326, 356, 366), such as an antenna array, that permits the respectiveapparatus to perform transmit “beamforming,” as described herein.Similarly, a receiver may include or be coupled to a plurality ofantennas (e.g., antennas 316, 326, 356, 366), such as an antenna array,that permits the respective apparatus to perform receive beamforming, asdescribed herein. In an aspect, the transmitter and receiver may sharethe same plurality of antennas (e.g., antennas 316, 326, 356, 366), suchthat the respective apparatus can only receive or transmit at a giventime, not both at the same time. A wireless communication device (e.g.,one or both of the transceivers 310 and 320 and/or 350 and 360) of theapparatuses 302 and/or 304 may also comprise a network listen module(NLM) or the like for performing various measurements.

The apparatuses 302 and 304 also include, at least in some cases,satellite positioning systems (SPS) receivers 330 and 370. The SPSreceivers 330 and 370 may be connected to one or more antennas 336 and376, respectively, for receiving SPS signals 338 and 378, respectively,such as global positioning system (GPS) signals, global navigationsatellite system (GLONASS) signals, Galileo signals, Beidou signals,Indian Regional Navigation Satellite System (NAVIC), Quasi-ZenithSatellite System (QZSS), etc. The SPS receivers 330 and 370 may compriseany suitable hardware and/or software for receiving and processing SPSsignals 338 and 378, respectively. The SPS receivers 330 and 370 requestinformation and operations as appropriate from the other systems, andperforms calculations necessary to determine the apparatus' 302 and 304positions using measurements obtained by any suitable SPS algorithm.

The TRP 304 and the network node 306 each include at least one networkinterfaces 380 and 390 for communicating with other network entities.For example, the network interfaces 380 and 390 (e.g., one or morenetwork access ports) may be configured to communicate with one or morenetwork entities via a wire-based or wireless backhaul connection. Insome aspects, the network interfaces 380 and 390 may be implemented astransceivers configured to support wire-based or wireless signalcommunication. This communication may involve, for example, sending andreceiving messages, parameters, and/or other types of information.

The apparatuses 302, 304, and 306 also include other components that maybe used in conjunction with the operations as disclosed herein. The UE302 includes processor circuitry implementing a processing system 332for providing functionality relating to, for example, sounding referencesignals (SRS) transmissions as disclosed herein, and for providing otherprocessing functionality. The TRP 304 includes a processing system 384for providing functionality relating to, for example, SRS configurationand reception as disclosed herein, and for providing other processingfunctionality. The network node 306 includes a processing system 394 forproviding functionality relating to, for example, SRS configuration asdisclosed herein, and for providing other processing functionality. Inan aspect, the processing systems 332, 384, and 394 may include, forexample, one or more general purpose processors, multi-core processors,ASICs, digital signal processors (DSPs), field programmable gate arrays(FPGA), or other programmable logic devices or processing circuitry.

The apparatuses 302, 304, and 306 include memory circuitry implementingmemory components 340, 386, and 396 (e.g., each including a memorydevice), respectively, for maintaining information (e.g., informationindicative of reserved resources, thresholds, parameters, and so on). Insome cases, the apparatuses 302, 304, and 306 may include RTTmeasurement reporting components 342, 388, and 398, respectively. TheRTT measurement reporting components 342, 388, and 398 may be hardwarecircuits that are part of or coupled to the processing systems 332, 384,and 394, respectively, that, when executed, cause the apparatuses 302,304, and 306 to perform the functionality described herein.Alternatively, the RTT measurement reporting components 342, 388, and398 may be memory modules (as shown in FIGS. 3A-C) stored in the memorycomponents 340, 386, and 396, respectively, that, when executed by theprocessing systems 332, 384, and 394, cause the apparatuses 302, 304,and 306 to perform the functionality described herein.

The UE 302 may include one or more sensors 344 coupled to the processingsystem 332 to provide movement and/or orientation information that isindependent of motion data derived from signals received by the WWANtransceiver 310, the WLAN transceiver 320, and/or the GPS receiver 330.By way of example, the sensor(s) 344 may include an accelerometer (e.g.,a micro-electrical mechanical systems (MEMS) device), a gyroscope, ageomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometricpressure altimeter), and/or any other type of movement detection sensor.Moreover, the sensor(s) 344 may include a plurality of different typesof devices and combine their outputs in order to provide motioninformation. For example, the sensor(s) 344 may use a combination of amulti-axis accelerometer and orientation sensors to provide the abilityto compute positions in 2D and/or 3D coordinate systems.

In addition, the UE 302 includes a user interface 346 for providingindications (e.g., audible and/or visual indications) to a user and/orfor receiving user input (e.g., upon user actuation of a sensing devicesuch a keypad, a touch screen, a microphone, and so on). Although notshown, the apparatuses 304 and 306 may also include user interfaces.

Referring to the processing system 384 in more detail, in the downlink,IP packets from the network node 306 may be provided to the processingsystem 384. The processing system 384 may implement functionality for anRRC layer, a packet data convergence protocol (PDCP) layer, a radio linkcontrol (RLC) layer, and a medium access control (MAC) layer. Theprocessing system 384 may provide RRC layer functionality associatedwith broadcasting of system information (e.g., master information block(MIB), system information blocks (SIBs)), RRC connection control (e.g.,RRC connection paging, RRC connection establishment, RRC connectionmodification, and RRC connection release), inter-RAT mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC servicedata units (SDUs), re-segmentation of RLC data PDUs, and reordering ofRLC data PDUs; and MAC layer functionality associated with mappingbetween logical channels and transport channels, scheduling informationreporting, error correction, priority handling, and logical channelprioritization.

The transmitter 354 and the receiver 352 may implement Layer-1functionality associated with various signal processing functions.Layer-1, which includes a physical (PHY) layer, may include errordetection on the transport channels, forward error correction (FEC)coding/decoding of the transport channels, interleaving, rate matching,mapping onto physical channels, modulation/demodulation of physicalchannels, and MIMO antenna processing. The transmitter 354 handlesmapping to signal constellations based on various modulation schemes(e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an orthogonalfrequency division multiplexing (OFDM) subcarrier, multiplexed with areference signal (e.g., pilot) in the time and/or frequency domain, andthen combined together using an inverse fast Fourier transform (IFFT) toproduce a physical channel carrying a time domain OFDM symbol stream.The OFDM stream is spatially precoded to produce multiple spatialstreams. Channel estimates from a channel estimator may be used todetermine the coding and modulation scheme, as well as for spatialprocessing. The channel estimate may be derived from a reference signaland/or channel condition feedback transmitted by the UE 302. Eachspatial stream may then be provided to one or more different antennas356. The transmitter 354 may modulate an RF carrier with a respectivespatial stream for transmission.

At the UE 302, the receiver 312 receives a signal through its respectiveantenna(s) 316. The receiver 312 recovers information modulated onto anRF carrier and provides the information to the processing system 332.The transmitter 314 and the receiver 312 implement Layer-1 functionalityassociated with various signal processing functions. The receiver 312may perform spatial processing on the information to recover any spatialstreams destined for the UE 302. If multiple spatial streams aredestined for the UE 302, they may be combined by the receiver 312 into asingle OFDM symbol stream. The receiver 312 then converts the OFDMsymbol stream from the time-domain to the frequency domain using a fastFourier transform (FFT). The frequency domain signal comprises aseparate OFDM symbol stream for each subcarrier of the OFDM signal. Thesymbols on each subcarrier, and the reference signal, are recovered anddemodulated by determining the most likely signal constellation pointstransmitted by the TRP 304. These soft decisions may be based on channelestimates computed by a channel estimator. The soft decisions are thendecoded and de-interleaved to recover the data and control signals thatwere originally transmitted by the TRP 304 on the physical channel. Thedata and control signals are then provided to the processing system 332,which implements Layer-3 and Layer-2 functionality.

In the UL, the processing system 332 provides demultiplexing betweentransport and logical channels, packet reassembly, deciphering, headerdecompression, and control signal processing to recover IP packets fromthe core network. The processing system 332 is also responsible forerror detection.

Similar to the functionality described in connection with the DLtransmission by the TRP 304, the processing system 332 provides RRClayer functionality associated with system information (e.g., MIB, SIBs)acquisition, RRC connections, and measurement reporting; PDCP layerfunctionality associated with header compression/decompression, andsecurity (ciphering, deciphering, integrity protection, integrityverification); RLC layer functionality associated with the transfer ofupper layer PDUs, error correction through ARQ, concatenation,segmentation, and reassembly of RLC SDUs, re-segmentation of RLC dataPDUs, and reordering of RLC data PDUs; and MAC layer functionalityassociated with mapping between logical channels and transport channels,multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing ofMAC SDUs from TBs, scheduling information reporting, error correctionthrough HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator from a referencesignal or feedback transmitted by the TRP 304 may be used by thetransmitter 314 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe transmitter 314 may be provided to different antenna(s) 316. Thetransmitter 314 may modulate an RF carrier with a respective spatialstream for transmission.

The UL transmission is processed at the TRP 304 in a manner similar tothat described in connection with the receiver function at the UE 302.The receiver 352 receives a signal through its respective antenna(s)356. The receiver 352 recovers information modulated onto an RF carrierand provides the information to the processing system 384.

In the UL, the processing system 384 provides demultiplexing betweentransport and logical channels, packet reassembly, deciphering, headerdecompression, control signal processing to recover IP packets from theUE 302. IP packets from the processing system 384 may be provided to thecore network. The processing system 384 is also responsible for errordetection.

For convenience, the apparatuses 302, 304, and/or 306 are shown in FIGS.3A-C as including various components that may be configured according tothe various examples described herein. It will be appreciated, however,that the illustrated blocks may have different functionality indifferent designs.

The various components of the apparatuses 302, 304, and 306 maycommunicate with each other over data buses 334, 382, and 392,respectively. The components of FIGS. 3A-C may be implemented in variousways. In some implementations, the components of FIGS. 3A-C may beimplemented in one or more circuits such as, for example, one or moreprocessors and/or one or more ASICs (which may include one or moreprocessors). Here, each circuit may use and/or incorporate at least onememory component for storing information or executable code used by thecircuit to provide this functionality. For example, some or all of thefunctionality represented by blocks 310 to 346 may be implemented byprocessor and memory component(s) of the UE 302 (e.g., by execution ofappropriate code and/or by appropriate configuration of processorcomponents). Similarly, some or all of the functionality represented byblocks 350 to 388 may be implemented by processor and memorycomponent(s) of the TRP 304 (e.g., by execution of appropriate codeand/or by appropriate configuration of processor components). Also, someor all of the functionality represented by blocks 390 to 398 may beimplemented by processor and memory component(s) of the network node 306(e.g., by execution of appropriate code and/or by appropriateconfiguration of processor components). For simplicity, variousoperations, acts, and/or functions are described herein as beingperformed “by a UE,” “by a base station,” “by a positioning entity,”etc. However, as will be appreciated, such operations, acts, and/orfunctions may actually be performed by specific components orcombinations of components of the UE, base station, positioning entity,etc., such as the processing systems 332, 384, 394, the transceivers310, 320, 350, and 360, the memory components 340, 386, and 396, the RTTmeasurement reporting modules 342, 388, and 398, etc.

FIG. 4 illustrates an exemplary wireless communications system 400according to aspects of the disclosure. In the example of FIG. 4 , a UE404 (which may correspond to any of the UEs described herein) isattempting to calculate an estimate of its position, or assist anotherentity (e.g., a base station or core network component, another UE, alocation server, a third party application, etc.) to calculate anestimate of its position. The UE 404 may communicate wirelessly with aplurality of base stations 402-1, 402-2, and 402-3 (collectively, basestations 402, and which may correspond to any of the base stationsdescribed herein) using RF signals and standardized protocols for themodulation of the RF signals and the exchange of information packets. Byextracting different types of information from the exchanged RF signals,and utilizing the layout of the wireless communications system 400(i.e., the base stations' locations, geometry, etc.), the UE 404 maydetermine its position, or assist in the determination of its position,in a predefined reference coordinate system. In an aspect, the UE 404may specify its position using a two-dimensional coordinate system;however, the aspects disclosed herein are not so limited, and may alsobe applicable to determining positions using a three-dimensionalcoordinate system, if the extra dimension is desired. Additionally,while FIG. 4 illustrates one UE 404 and three base stations 402, as willbe appreciated, there may be more UEs 404 and more base stations 402.

To support position estimates, the base stations 402 may be configuredto broadcast reference RF signals (e.g., PRS, NRS, CRS, TRS, CSI-RS,PSS, or SSS, etc.) to UEs 404 in their coverage area to enable a UE 404to measure characteristics of such reference RF signals. For example,the UE 404 may measure the time of arrival (ToA) of specific referenceRF signals (e.g., PRS, NRS, CRS, CSI-RS, etc.) transmitted by at leastthree different base stations 402-1, 402-2, and 402-3 and may use theRTT positioning method to report these ToAs (and additional information)back to the serving base station 402 or another positioning entity(e.g., location server 230, LMF 270).

In an aspect, although described as the UE 404 measuring reference RFsignals from a base station 402, the UE 404 may measure reference RFsignals from one of multiple TRPs supported by a base station 402. Wherethe UE 404 measures reference RF signals transmitted by a TRP supportedby a base station 402, the at least two other reference RF signalsmeasured by the UE 404 to perform the RTT procedure would be from TRPssupported by base stations 402 different from the first base station 402and may have good or poor signal strength at the UE 404.

In order to determine the position (x, y) of the UE 404, the entitydetermining the position of the UE 404 needs to know the locations ofthe base stations 402, which may be represented in a referencecoordinate system as (x_(k), y_(k)), where k=1, 2, 3 in the example ofFIG. 4 . Where one of the base stations 402 (e.g., the serving basestation) or the UE 404 determines the position of the UE 404, thelocations of the involved base stations 402 may be provided to theserving base station 402 or the UE 404 by a location server withknowledge of the network geometry (e.g., location server 230, LMF 270).Alternatively, the location server may determine the position of the UE404 using the known network geometry.

Either the UE 404 or the respective base station 402 may determine thedistance 410 (d_(k), where k=1, 2, 3) between the UE 404 and therespective base station 402. Specifically, the distance 410-1 betweenthe UE 404 and base station 402-1 is d₁, the distance 410-2 between theUE 404 and base station 402-2 is d₂, and the distance 410-3 between theUE 404 and base station 402-3 is d₃. In an aspect, determining the RTTof signals exchanged between the UE 404 and any base station 402 can beperformed and converted to a distance 410 (d_(k)). As discussed furtherbelow, RTT techniques can measure the time between sending a signalingmessage (e.g., reference RF signals) and receiving a response. Thesemethods may utilize calibration to remove any processing delays. In someenvironments, it may be assumed that the processing delays for the UE404 and the base stations 402 are the same. However, such an assumptionmay not be true in practice.

Once each distance 410 is determined, the UE 404, a base station 402, orthe location server (e.g., location server 230, LMF 270) can solve forthe position (x, y) of the UE 404 by using a variety of known geometrictechniques, such as, for example, trilateration. From FIG. 4 , it can beseen that the position of the UE 404 ideally lies at the commonintersection of three semicircles, each semicircle being defined byradius d_(k) and center (x_(k), y_(k)), where k=1, 2, 3.

In some instances, additional information may be obtained in the form ofan angle of arrival (AoA) or angle of departure (AoD) that defines astraight line direction (e.g., which may be in a horizontal plane or inthree dimensions) or possibly a range of directions (e.g., for the UE404 from the location of a base station 402). The intersection of thetwo directions at or near the point (x, y) can provide another estimateof the location for the UE 404.

A position estimate (e.g., for a UE 404) may be referred to by othernames, such as a location estimate, location, position, position fix,fix, or the like. A position estimate may be geodetic and comprisecoordinates (e.g., latitude, longitude, and possibly altitude) or may becivic and comprise a street address, postal address, or some otherverbal description of a location. A position estimate may further bedefined relative to some other known location or defined in absoluteterms (e.g., using latitude, longitude, and possibly altitude). Aposition estimate may include an expected error or uncertainty (e.g., byincluding an area or volume within which the location is expected to beincluded with some specified or default level of confidence).

FIG. 5 is an exemplary diagram 500 showing exemplary timings of RTTmeasurement signals exchanged between a TRP 502 (e.g., any of the basestations, gNBs, cells, etc. described herein) and a UE 504 (e.g., any ofthe UEs described herein), according to aspects of the disclosure. Inthe example of FIG. 5 , the TRP 502 sends an RTT measurement signal 510(e.g., PRS, NRS, CRS, CSI-RS, etc.) to the UE 504 at time T₁. The RTTmeasurement signal 510 has some propagation delay T_(Prop) as it travelsfrom the TRP 502 to the UE 504. At time T₂ (the ToA of the RTTmeasurement signal 510 at the UE 504), the UE 504 receives/measures theRTT measurement signal 510. After some UE processing time, the UE 504transmits an RTT response signal 520 (e.g., an SRS, UL-PRS) at time T₃.After the propagation delay T_(Prop), the TRP 502 receives/measures theRTT response signal 520 from the UE 504 at time T₄ (the ToA of the RTTresponse signal 520 at the TRP 502).

In order to identify the ToA (e.g., T₂) of an RF signal (e.g., an RTTmeasurement signal 510) transmitted by a given network node, thereceiver (e.g., UE 504) first jointly processes all the resourceelements (REs) on the channel on which the transmitter (e.g., TRP 502)is transmitting the RF signal, and performs an inverse Fourier transformto convert the received RF signals to the time domain. The conversion ofthe received RF signals to the time domain is referred to as estimationof the channel energy response (CER). The CER shows the peaks on thechannel over time, and the earliest “significant” peak should thereforecorrespond to the ToA of the RF signal. Generally, the receiver will usea noise-related quality threshold to filter out spurious local peaks,thereby presumably correctly identifying significant peaks on thechannel. For example, the UE 504 may chose a ToA estimate that is theearliest local maximum of the CER that is at least X decibels (dB)higher than the median of the CER and a maximum Y dB lower than the mainpeak on the channel. The receiver determines the CER for each RF signalfrom each transmitter in order to determine the ToA of each RF signalfrom the different transmitters.

The RTT response signal 520 may explicitly include the differencebetween time T₃ and time T₂ (i.e., T_(Rx→Tx)). Alternatively, it may bederived from the timing advance (TA), i.e., the relative UL/DL frametiming and specification location of UL reference signals. (Note thatthe TA is usually the RTT between the TRP 502 and the UE 504, or doublethe propagation time in one direction.) Using this measurement and thedifference between time T₄ and time T₁ (i.e., T_(Tx→Rx)), the TRP 502can calculate the distance to the UE 504 as:

$\begin{matrix}{d = {{\frac{1}{2c}\left( {T_{{Tx}\rightarrow{Rx}} - T_{{Rx}\rightarrow{Tx}}} \right)} = {{\frac{1}{2c}\left( {T_{2} - T_{1}} \right)} + {\frac{1}{2c}\left( {T_{4} - T_{3}} \right)}}}} & (1)\end{matrix}$

where c is the speed of light.

Note that the UE 504 can perform an RTT procedure with multiple TRPs502. However, the RTT procedure does not require synchronization betweenthese base stations 502. In the multi-RTT positioning procedure, thebasic procedure is repeatedly performed between the UE and multiple TRPs(e.g., base stations gNBs, eNBs, cells, etc.). The basic procedure is asfollows:

-   -   1. gNB transmits downlink (DL) reference signal (RS) at time T₁        (also referred to as T_(gNB,Tx));    -   2. DL RS arrives at the UE at time T₂ (also referred to as        T_(UE,Rx));    -   3. UE transmits uplink (UL) RS at time T₃ (also referred to as        T_(UE,Tx));    -   4. UL RS arrives at the gNB at time T₄ (also referred to as        T_(gNB,Rx)).        Positioning reference signal (PRS) is an example of the DL RS        and sounding reference signal (SRS) is an example of the UL RS.        With the knowledge of (T₄-T₁) and (T₃-T₂), the following        equation may be generated:

$\begin{matrix}{{RTT} = {\frac{2d}{c} = {{\left( {T_{4} - T_{1}} \right) - \left( {T_{3} - T_{2}} \right)} = {\left( {T_{4} - T_{1}} \right) + {\left( {T_{2} - T_{3}} \right).}}}}} & (2)\end{matrix}$

In conventional wireless networks (e.g., LTE), an E-CID (EnhancedCell-ID) procedure is defined to determine the UE position. In thisprocedure, the UE measures its surroundings and provides measurementreports to the network. One measurement report may include measurementsresults for up to 32 TRPs. For a measured TRP, the measurement resultsincludes:

-   -   UE_(Rx-Tx);    -   cell ID;    -   RSRP/RSRQ (reference signal received power/reference signal        received quality) for the DL measurement (RRM measurements if        available);    -   SFN (system frame number) of the frame of that cell in which the        UE considers the DL measurement to be valid.

The parameter UE_(Rx-Tx) (referred to as “ue-RxTxTimeDiff” in LTE) isdefined as T_(UE,Rx) T_(UE,Tx) in which T_(UE,Rx) is the UE receivedtiming of a downlink (DL) radio frame from the serving TRP, andT_(UE,Tx) is the UE transmit time of corresponding uplink (UL) radioframe to the serving TRP. This is visually presented in FIG. 6 . Asseen, the “ue-RxTxTimeDiff” is the difference between the transmittiming of uplink frame #i at the UE and the received timing of downlinkframe #i also at the UE. Even though up to 32 TRPs can be measured, theue-RxTxTimeDiff is provided only for the UE's primary TRP inconventional systems.

In LTE (Ts=32.5 nsec), the UE_(Rx-Tx) is measured using 12 bits, withvarying resolution depending on the size of the UE_(Rx-Tx). According toLTE, the reporting range of the UE_(Rx-Tx) is defined from 0 to20472T_(s) with 2T_(s) resolution for UE_(Rx-Tx) less than 4096 T_(s)and 8 T_(s) for UE_(Rx-Tx) equal to or greater than 4096T_(s). Thefollowing table defines the mapping of measured quantity (copied from3GPP, TS 36.355, Table 9.1.9.2-1).

TABLE 9.1.9.2-1 UE Rx-Tx time difference measurement report mappingReported value Measured quantity value Unit RX-TX_TIME_DIFFERENCE_0000T_(UE Rx-Tx) < 2 T_(s) RX-TX_TIME_DIFFERENCE_0001 2 ≤ T_(UE Rx-Tx) < 4T_(s) RX-TX_TIME_DIFFERENCE_0002 4 ≤ T_(UE Rx-Tx) < 6 T_(s) . . . . . .. . . RX-TX_TIME_DIFFERENCE_2046 4092 ≤ T_(UE Rx-Tx) < 4094 T_(s)RX-TX_TIME_DIFFERENCE_2047 4094 ≤ T_(UE Rx-Tx) < 4096 T_(s)RX-TX_TIME_DIFFERENCE_2048 4096 ≤ T_(UE Rx-Tx) < 4104 T_(s)RX-TX_TIME_DIFFERENCE_2049 4104 ≤ T_(UE Rx-Tx) < 4112 T_(s) . . . . . .. . . RX-TX_TIME_DIFFERENCE_4093 20456 ≤ T_(UE Rx-Tx) < 20464 T_(s)RX-TX_TIME_DIFFERENCE_4094 20464 ≤ T_(UE Rx-Tx) < 20472 T_(s)RX-TX_TIME_DIFFERENCE_4095 20472 ≤ T_(UE Rx-Tx) T_(s)

For example, if the UE reports RX_TX_TIME_DIFFERENCE_0002, this meansthat the UE_(Rx-Tx) of the UE and the primary TRP is in between 130 nsecand 195 nsec, i.e., an uncertainty of 65 nsec.

In NR, it is expected that one measurement report and for a given TRP k(not just for the primary TRP), the UE will include:

-   -   the UE_(Rx-Tx,k)=T_(UE,Rx,k)−T_(UE,Tx,k);    -   TRP ID (or PRS ID) and SRS ID;    -   SFN of the frame of the serving TRP during which the reported        measurements is valid;    -   RSRP/RSRQ for the DL measurement.

For example, in the scenario of FIG. 6 , the measurement report willinclude the Rx-Tx time difference measurements of multiple TRPs (e.g.,serving gNB1 and neighbor gNB2). The Rx-Tx time difference (UE_(Rx-Tx,k)(time_diff)) for each TRP k is defined as T_(UE,Rx,k)-T_(UE,Tx,k) inwhich T_(UE,Rx,k) is the UE received timing of a downlink (DL) radiosubframe from the TRP k, and T_(UE,Tx,k) is the UE transmit time ofcorresponding uplink (UL) radio subframe to the TRP k.

The following problems/issues are identified. First, there can be manyTRPs included in the measurement report. In NR, there can be up to 96TRPs for RRM purposes. Therefore, measurement reporting for positioningmay need to be extended at least to this number. However, this canincrease the reporting overhead significantly. Second, there can bedifferent numerologies used in NR for UL and DL. This means that thestep size Ts can change and is not necessarily fixed as in LTE.

Regarding numerology, LTE supports a single numerology (subcarrierspacing (15 kHz) and symbol length). In contrast, 5G NR may supportmultiple numerologies, for example, subcarrier spacings of 15 kHz, 30kHz, 60 kHz, 120 kHz and 240 kHz or greater may be available. Table 1provided below lists some various parameters for different 5G NRnumerologies.

TABLE 1 Max. nominal system BW Subcarrier Symbol (MHz) spacing Symbols/slots/ slots/ slot duration with 4K (kHz) slot subframe frame (ms)(μsec) FFT size 15 14 1 10 1 66.7 50 30 14 2 20 0.5 33.3 100 60 14 4 400.25 16.7 100 120 14 8 80 0.125 8.33 400 240 14 16 160 0.0625 4.17 800

Throughout this specification, unless otherwise noted, the size ofvarious fields in the time domain may be expressed in time unitsT_(C)=1/(Δf_(max)*N_(f)) where Δf_(max)=480*10³ Hz and N_(f)=4096. Theconstant k=T_(S)/T_(C)=64 where T_(s)=1/(Δf_(ref)*N_(f,ref)) in whichΔf_(ref)=15*10³ Hz and N_(f,ref)=2048.

As indicated, the conventional measurement reports have the followingissues. (1) Reporting the UE_(Rx-Tx) (or time_diff) measurements for upto 96 TRPs (and this number may increase in the future) can requiresignificant overhead; and (2) the existing LTE resolution may not besufficient to provide positioning accuracy. To address these and otherissues, techniques/processes are proposed to achieve one or both ofenhanced resolution (and hence positioning accuracy) without increasingreporting overhead and reduced reporting overhead without sacrificingaccuracy.

Regarding the resolution, the LTE's resolution of 2 Ts (65 nsec) or 8 Ts(260 nsec) may not provide sufficient accuracy in positioningdetermination. To enhance the resolution and hence increase theaccuracy, in one or more aspects, it is proposed to have the step sizebe dependent on T_(C)=0.509 nsec (based on highest sampling rate) andthe numerology factor “u”. For example, the step size T_(S) may beT_(C)2^(u), where “u” is one of 0, 1, 2, 3, 4, 5, 6. For example, if uis zero, then the step size T_(S)=0.5 nsec. This is significantlysmaller than the LTE's step size of 32.5 nsec meaning that a much finertiming resolution can be obtained, which in turn can increase theaccuracy of positioning. Generally, the resolution can be based on thenumerology according to KT_(c)2^(u), where the value of K and u willgenerally decrease as the subcarrier spacing increases. Table 2 belowprovides values in nsec for KT_(c)2^(u) for various values of K andnumerology factor u.

TABLE 2 u 0 1 2 3 4 5 6 K 1 0.509 1.017 2.035 4.069 8.138 16.276 32.5522 1.017 2.035 4.069 8.138 16.276 32.552 65.104 3 1.526 3.052 6.10412.207 24.414 48.828 97.656

For a numerology with subcarrier spacing of 15 kHz, it may be desirableto keep consistency with the LTE. Accordingly, for 15 kHz, then K=3 andu=6, which results in the same value 97.656 nsec as 3·T_(s). However,for other 5G NR numerologies, the values of u can vary.

It is mentioned above that numerologies for DL RS (e.g., PRS) and UL RS(e.g., SRS) in NR can be different. Regarding the UE_(Rx-Tx) included inthe measurement report, the following options may be implemented:

-   -   Option 1: Each UE_(Rx-Tx) measurement has a configured        numerology factor that is independent of the subcarrier spacing        used for the DL RS or the UL RS.    -   Option 2: Use the largest subcarrier spacing between the DL RS        and the UL RS corresponding to each UE_(Rx-Tx) measurement.    -   Option 3: Use the smallest subcarrier spacing between the DL RS        and the UL    -   RS corresponding to each UE_(Rx-Tx) measurement.    -   Option 4: The numerology factor is a function of bandwidths        (BWs) of DL RS and UL RS.    -   Option 5: All UE_(Rx-Tx) measurements have the same numerology        factor.    -   Option 6: Groups of UE_(Rx-Tx) measurements have the same        numerology factor.

For example, in option 1, a numerology factor is configured for eachUE_(Rx-Tx,k) (i.e., time_diff) measurement, which is independent of thesubcarrier spacing (SCS) of the DL RS and UL RS used to measure theT_(UE,Tx,k), T_(UE,Tx,k) components of the UE_(Rx-Tx,k) measurement. Insome ways, this can be said to reflect the measurement capabilities ofthe UE. For example, if there is a high confidence regarding the UE'smeasurements for a particular TRP k, then the numerology factor may beconfigured as u=2 (for 120 kHz SCS). In this instance, the step sizeT_(S)=2.035 nsec. Generally, a smaller numerology factor would inferbetter accuracy. In the foregoing example for the 120 Khz SCS, thesampling rate is 1/4096*120, which correspond to 2.035 nsec, and thenumerology factor u being u=2.

If the same 12 bits and the same discretization as in LTE is used (2 Tsresolution), then the uncertainty for each discretized entry is reducedfrom 65 nsec (for LTE) to 4.069 nsec. For example, ifRX_TX_TIME_DIFFERENCE_0002 is reported, then for LTE, the actualUE_(Rx-Tx), ranges between 130 nsec and 195 nsec. On the other hand, ifthe same RX_TX_TIME_DIFFERENCE_0002 is reported for the configurednumerology, then the actual UE_(Rx-Tx), ranges between 8.138 nsec and12.210 nsec. In short, accuracy is enhanced without increasing thereporting overhead.

In option 2, the numerology factor used in reporting the UE_(Rx-Tx,k)for a TRP k is implicit. In general, larger SCS implies a largerbandwidth (higher sampling rate), which in turn implies a higherresolution and accuracy. In option 2, the step size is determined basedthe larger of the SCS used for DL RS and UL RS signals. For example, ifthe SCS for the DL RS is 120 kHz (corresponding to u=2) and the SCS forthe UL RS is 60 kHz (corresponding to u=3), then the step sizeT_(s)=4.069 nsec. This means that the uncertainty for each discretizedTIME_DIFFERENCE value is 8.138 nsec.

Option 3 is similar to option 2 in that the numerology factor isimplicit. The difference is that instead of using the larger SCS, inoption 3, the smaller SCS is used. Thus, option 2 may be viewed as the“optimistic approach” while option 3 may be viewed as the “conservativeapproach”. Then for the same scenario described above, the step sizeT_(S)=8.138 nsec, meaning that the uncertainty for each discretizedTIME_DIFFERENCE value increases to 16.276 nsec as compared to option 2.

Option 4 is another instance in which the numerology factor isimplicitly derived. As mentioned, larger bandwidth (BW) is usuallyindicative of greater accuracy. In some aspects, the numerology factormay be based on the DL RS bandwidth or the UL RS bandwidth. In furtheraspects, if the PRS, SRS are respectively used as the DL RS, UL RS, thenthe numerology factor may be a function based on min(PRS BW, SRS BW).Alternatively, the numerology factor may be a function based on max(PRSBW, SRS BW). In an aspect, there may be a mapping between the bandwidthsand the numerology factors.

Option 5 is simple in that for a given measurement report, the samenumerology factor u is assumed for all UE_(Rx-Tx), measurements. Thenetwork entity may configure the UE with the numerology factor u in thePRS measurement report.

In option 6, the UE_(Rx-Tx), measurements are grouped, e.g., such thatthe numerology factor is the same for all members in each group (sameintra-group numerology factor). Of course, different groups can havedifferent numerology factors (independent inter-group numerologyfactors). The numerology factors in option 6 may be arrived at throughany of the options 1-4.

One benefit of grouping the UE_(Rx-Tx) measurements is that thereporting overhead can be reduced. As will be made clear from thedescription below, option 6 is also referred to as “differentialreporting”. Broadly, the differential reporting is as follows:

-   -   For each group, determine/choose a reference TRP (e.g., gNB) of        that group. The UE_(Rx-Tx), of the reference TRP is the        reference UE_(Rx-Tx).    -   For each of the other members of the group, the UE_(Rx-Tx) of        that member is reported as a differential with respect to the        reference UE_(Rx-Tx).

The differential UE_(Rx-Tx) bit width can be less than the fullUE_(Rx-Tx) bit width. However, it is preferred that the differentialUE_(Rx-Tx) bit width be wide enough to cover the maximum cyclic prefix(CP) length on the UL or the DL with the same resolution as that usedfor the UE_(Rx-Tx). As an illustration, assume a legacy UE_(Rx-Tx) widthof 12 bits with 2 Ts resolution. Also assume that all TRPs in a groupare received within a CP of 30 kHz SCS (2.4 usec) with a Ts=16.3 nsec.Then

${\log_{2}\left( \frac{2400}{2*16.3} \right)} = 7$bits are sufficient to report each differential UE_(Rx-Tx). Theresolution and the maximum size of the differential bit width can beconfigured per group to achieve even greater compression gains.

The differential reporting is useful where capacity may be an issue,such as in the Physical Uplink Control Channel (PUCCH). However, evenwhen the capacity is not a significant issue, such as in Physical UplinkShared Control Channel (PUSCH), the differential reporting can still beuseful. As an option, the differential step size, i.e., the step sizefor the differential UE_(Rx-Tx), need not be the same as the referencestep size of the reference UE_(Rx-Tx). This can be useful incircumstances such as when multiple far away TRPs are in a group, butthe relative differences among the member TRPs is slight.

In one aspect, the groups can be explicitly configured along with thereference TRP for each group. For example, a network entity mayexplicitly configure the groups in the DL RS measurement configurationor the UE in the measurement report. In another aspect, the groups canbe implicitly derived by the DL RS configurations. For example, when PRSis used, the following guidance can be used:

-   -   The TRPs that transmit PRS on the same slot belong to one group;    -   The TRPs that transmit PRS on the same frame belong to one        group;    -   The TRPs that transmit PRS on the same symbols belong to one        group;    -   The SRS configured to the UE is supposed to be received the        TRPs:        -   The SRS configuration is associated with a specific set of            TRPs. The set of such TRPs defines a group.    -   For different timing advance (TA) command, or different timing        advance group (TAG), the TRP groups are defined (e.g., by the        UE) accordingly.

FIG. 7 illustrates an exemplary method performed by a UE for providingmeasurement reports. At 710, the UE receives a plurality of downlinkreference signals (DL RSs) from a plurality of TRPs (e.g., plurality ofgNBs). At 720, the UE transmits a corresponding plurality of uplinkreference signals (UL RSs) to the plurality of TRPs. PRSs are examplesof the DL RSs and/or SRSs are examples of the UL RSs.

At 730, the UE determines the numerology factors for all TRPs. Asdiscussed in the foregoing, the time_diff UE_(Rx-Tx,k) for each TRP k isdefined as T_(UE,Rx,k)-T_(UE,Tx,k) in which T_(UE,Rx,k) is the UEreceived timing of a downlink (DL) radio subframe from the TRP k, andT_(UE,Tx,k) is the UE transmit time of corresponding uplink (UL) radiosubframe to the TRP k. Also, as discussed in the foregoing, the accuracyof the UE_(Rx-Tx,k) depends on the numerology factors which determinesthe step size T_(s,k) of each TRP.

In the simplest case, the same numerology factors, and hence the samestep size may be determined for all. This corresponds to option 5discussed above. However, the numerology factor can be tailored to eachof the TRPs k to enhance accuracy and/or reduce overhead. As discussedin the foregoing, the T_(s,k) for each TRP k represents resolution of aUE received timing of the DL RS from the TRP k and/or a resolution of aUE transmit timing of the UL RS to the TRP k. In one aspect, thenumerology factor of a TRP k is configured independently of the SCS ofthe DL RS received from the TRP k and independent of the SCS of the ULRS transmitted to the TRP k. This corresponds to option 1 discussedabove.

Alternatively, the numerology factor of a TRP k can be determined basedon some characteristics/parameters of the DL RS received from the TRP kand/or of the UL RS transmitted to the TRP k. For example, the step sizenumerology factor for TRP k can be determined based on a largersubcarrier spacing (SCS) of the DL RS and the UL RS. This corresponds tooption 2 discussed above. As another example, the numerology factor forTRP k can be determined based on a smaller SCS of the DL RS and the ULRS.

Instead of or in addition thereto, the bandwidths of DL RS and/or UL RSmaybe used to determine the numerology factor. For example, thenumerology factor may be based on the DL RS bandwidth, the UL RSbandwidth, a function min(DL RS bandwidth, UL RS bandwidth) or max(DL RSbandwidth, UL RS bandwidth). These correspond to option 4 discussedabove.

At 740, the UE generates the measurement report for all TRPs k based onthe numerology factors. The measurement report includes the time_diffUE_(Rx-Tx,k) for each TRP k. To report the time_diffs UE_(Rx-Tx), forthe TRPs, the measurement report can include, for each TRP k, atime_diff field configured to hold the UE_(Rx-Tx) of the TRP k. In oneaspect, if the UE_(Rx-Tx) of the TRPs are individually generated andreported, then the entire width of the time_diff field will be used forthe UE_(Rx-Tx) of each of the TRPs. The UE transmits the measurementreport to its serving TRP at 750. The measurement report includes areceive-transmit (Rx-Tx) time difference (e.g., UE_(Rx-Tx,k)) for eachTRP (e.g., TRP k).

FIG. 8 illustrates an example process performed by the UE to implementblock 740. By grouping the UE_(Rx-Tx) of the TRPs as discussed above(corresponding to option 6), the reporting overhead can be reduced. At810, the UE determines the TRP groups. At 820, the UE determines areference TRP (e.g., reference gNB) for each TRP group. Thisautomatically determines the reference time_diff UE_(Rx-Tx) of thegroup. In one aspect, the TRP groups may be determined such that withina TRP group, the numerology factor is the same for all members of theTRP group.

The TRP groups can be explicitly configured (e.g., by the network and/orthe UE) along with the reference TRP inside each TRP group.Alternatively, the TRP groups can be determined implicitly. For example,the TRP groups can be determined such that for at least one TRP group,all member TRPs transmit positioning reference signals (PRSs) on a sameslot. As another example, the TRP groups can be determined such that forat least one TRP group, all member TRPs transmit the PRSs on a sameframe. As a further example, the TRP groups can be determined such thatfor at least one TRP group, all member TRPs transmit the PRSs on samesymbols.

The TRP groups can also be determined based on the sounding referencesignals (SRS). For example, an SRS configuration is associated withspecific TRPs. In this instance, the set of such TRPs can be a TRPgroup. Also, the TRPs groups can be determined based on different PUCCHcommands, or different timing advance groups (TAGs).

FIG. 9 illustrates an exemplary method performed by a network entity. At910, the network entity (e.g., location server, serving TPR, other TRP,etc.) receives a measurement report from the UE. At 920, the networkentity can determine the position of the UE from the measurement.Alternatively or in addition thereto, the network entity (e.g., servingTRP) can forward the measurement to a location server (e.g., LMU,E-SMLC, LMF, GMLC, etc.) for the UE position to be determined.

FIG. 10 illustrates an example network entity 1000, which can be aserving TRP, location server, etc. represented as a series ofinterrelated functional modules connected by a common bus. Each of themodules may be implemented in hardware or as a combination of hardwareand software. For example, the modules may be implemented as anycombination of the apparatus 304 or 306. A module for receiving ameasurement report 1010 may correspond at least in some aspects to, forexample, a communication device, such as communication device 350 inFIG. 3B or 390 in FIG. 3C and/or a processing system, such as processingsystem 384 in FIG. 3B, or 394 in FIG. 3C, as discussed herein. A modulefor determining the UE position 1020 may correspond at least in someaspects to, for example, a processing system, such as processing system384 in FIG. 3B, or 394 in FIG. 3C, as discussed herein. An optionalmodule for forwarding the measurement report 1030 may correspond atleast in some aspects to, for example, a communication device, such ascommunication device 350 in FIG. 3B or 390 in FIG. 3C and/or aprocessing system, such as processing system 384 in FIG. 3B, or 394 inFIG. 3C, as discussed herein.

FIG. 11 illustrates an example user equipment 1100 represented as aseries of interrelated functional modules connected by a common bus.Each of the modules may be implemented in hardware or as a combinationof hardware and software. For example, the modules may be implemented asany combination of the apparatus 302. A module for receiving a pluralityof reference signals 1110 may correspond at least in some aspects to,for example, a communication device, such as communication device 310 inFIG. 3A and/or a processing system, such as processing system 332 inFIG. 3A, as discussed herein. A module for transmitting a plurality ofuplink reference signals 1120 may correspond at least in some aspectsto, for example, a communication device, such as communication device310 in FIG. 3A and/or a processing system, such as processing system 332in FIG. 3A, as discussed herein. A module for determining numerologyfactors 1130 may correspond at least in some aspects to, for example, aprocessing system, such as processing system 332 in FIG. 3A, asdiscussed herein. A module for generating measurement report 1140 maycorrespond at least in some aspects to, for example, a processingsystem, such as processing system 332 in FIG. 3A, as discussed herein. Amodule for transmitting a measurement report 1150 may correspond atleast in some aspects to, for example, a communication device, such ascommunication device 310 in FIG. 3A and/or a processing system, such asprocessing system 332 in FIG. 3A, as discussed herein.

The functionality of the modules of FIGS. 10-11 may be implemented invarious ways consistent with the teachings herein. In some designs, thefunctionality of these modules may be implemented as one or moreelectrical components. In some designs, the functionality of theseblocks may be implemented as a processing system including one or moreprocessor components. In some designs, the functionality of thesemodules may be implemented using, for example, at least a portion of oneor more integrated circuits (e.g., an ASIC). As discussed herein, anintegrated circuit may include a processor, software, other relatedcomponents, or some combination thereof. Thus, the functionality ofdifferent modules may be implemented, for example, as different subsetsof an integrated circuit, as different subsets of a set of softwaremodules, or a combination thereof. Also, it will be appreciated that agiven subset (e.g., of an integrated circuit and/or of a set of softwaremodules) may provide at least a portion of the functionality for morethan one module.

In addition, the components and functions represented by FIGS. 10-11 ,as well as other components and functions described herein, may beimplemented using any suitable means. Such means also may beimplemented, at least in part, using corresponding structure as taughtherein. For example, the components described above in conjunction withthe “module for” components of FIGS. 10-11 also may correspond tosimilarly designated “means for” functionality. Thus, in some aspectsone or more of such means may be implemented using one or more ofprocessor components, integrated circuits, or other suitable structureas taught herein.

Those of skill in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those of skill in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a DSP, an ASIC, an FPGA, orother programmable logic device, discrete gate or transistor logic,discrete hardware components, or any combination thereof designed toperform the functions described herein. A general purpose processor maybe a microprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices,e.g., a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The methods, sequences and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art. An exemplary storage medium is coupled to the processor suchthat the processor can read information from, and write information to,the storage medium. In the alternative, the storage medium may beintegral to the processor. The processor and the storage medium mayreside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). Inthe alternative, the processor and the storage medium may reside asdiscrete components in a user terminal.

In one or more exemplary aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects of thedisclosure, it should be noted that various changes and modificationscould be made herein without departing from the scope of the disclosureas defined by the appended claims. The functions, steps and/or actionsof the method claims in accordance with the aspects of the disclosuredescribed herein need not be performed in any particular order.Furthermore, although elements of the disclosure may be described orclaimed in the singular, the plural is contemplated unless limitation tothe singular is explicitly stated.

What is claimed is:
 1. A method performed by a user equipment (UE), themethod comprising: receiving a plurality of downlink reference signals(DL RSs) from a plurality of transmission reception points (TRPs);transmitting at least one uplink reference signal (UL RS) to theplurality of TRPs; and transmitting a measurement report for theplurality of TRPs to a network entity, wherein the measurement reportincludes a receive-transmit (Rx-Tx) time difference measurement for atleast two TRPs of the plurality of TRPs, and wherein a step size forreporting the Rx-Tx time difference measurement is based on a time unitT_(c) and one or more numerology factors.
 2. The method of claim 1,wherein the Rx-Tx time difference measurement for each TRP k, where k isan integer, of the plurality of TRPs is defined asT_(UE,Rx,k)−T_(UE,Tx,k) in which T_(UE,Rx,k) is a time that the UEreceives a downlink (DL) radio subframe from the TRP k, and T_(UE,Tx,k)is a time that the UE transmits a corresponding uplink (UL) radiosubframe to the TRP k.
 3. The method of claim 1, wherein each DL RS is apositioning reference signal (PRS) and the at least one UL RS is asounding reference signal (SRS) for positioning.
 4. The method of claim1, wherein a numerology factor of the one or more numerology factors ofa TRP k, where k is an integer, of the plurality of TRPs is determinedbased on at least one of one or more characteristics of a DL RS receivedfrom the TRP k or one or more characteristics of a UL RS transmitted tothe TRP k.
 5. The method of claim 1, wherein the measurement reportincludes, for a TRP k, where k is an integer, of the plurality of TRPs,an Rx-Tx time difference field configured to hold an Rx-Tx timedifference measurement of the TRP k, and for at least one TRP n, where nis an integer, of the plurality of TRPs, an Rx-Tx time difference fieldconfigured to hold an Rx-Tx time difference measurement of the TRP n. 6.The method of claim 1, wherein the measurement report includes: areference Rx-Tx time difference measurement; and a differential Rx-Txtime difference measurement.
 7. The method of claim 6, wherein a numberof bits for representing the differential Rx-Tx time differencemeasurement is less than a number of bits for representing the referenceRx-Tx time difference measurement.
 8. A user equipment (UE) comprising:a memory; at least one transceiver; and a processor coupled to thememory and the at least one transceiver, wherein the processor isconfigured to: receive, via the at least one transceiver, a plurality ofdownlink reference signals (DL RSs) from a plurality of transmissionreception points (TRPs); transmit, via the at least one transceiver, atleast one uplink reference signal (UL RS) to the plurality of TRPs; andtransmit, via the at least one transceiver, a measurement report for theplurality of TRPs to a network entity, wherein the measurement reportincludes a receive-transmit (Rx-Tx) time difference measurement for atleast two TRPs of the plurality of TRPs, and wherein a step size forreporting the Rx-Tx time difference measurement is based on a time unitT_(c) and one or more numerology factors.
 9. The UE of claim 8, whereinthe Rx-Tx time difference measurement for each TRP k, where k is aninteger, of the plurality of TRPs is defined as T_(UE,Rx,k) T_(UE,Tx,k)in which T_(UE,Rx,k) is a time that the UE receives a downlink (DL)radio subframe from the TRP k, and T_(UE,Tx,k) is a time that the UEtransmits a corresponding uplink (UL) radio subframe to the TRP k. 10.The UE of claim 8, wherein each DL RS is a positioning reference signal(PRS) and the at least one UL RS is a sounding reference signal (SRS)for positioning.
 11. The UE of claim 8, wherein a numerology factor ofthe one or more numerology factors of a TRP k, where kis an integer, ofthe plurality of TRPs is determined based on at least one of one or morecharacteristics of a DL RS received from the TRP k or one or morecharacteristics of a UL RS transmitted to the TRP k.
 12. The UE of claim8, wherein the measurement report includes, for a TRP k, where k is aninteger, of the plurality of TRPs, an Rx-Tx time difference fieldconfigured to hold an Rx-Tx time difference measurement of the TRP k,and for at least one TRP n, where n is an integer, of the plurality ofTRPs, an Rx-Tx time difference field configured to hold an Rx-Tx timedifference measurement of the TRP n.
 13. The UE of claim 8, wherein themeasurement report includes: a reference Rx-Tx time differencemeasurement; and a differential Rx-Tx time difference measurement. 14.The UE of claim 13, wherein a number of bits for representing thedifferential Rx-Tx time difference measurement is less than a number ofbits for representing the reference Rx-Tx time difference measurement.15. A user equipment (UE) comprising: means for receiving a plurality ofdownlink reference signals (DL RSs) from a plurality of transmissionreception points (TRPs); means for transmitting at least one uplinkreference signal (UL RS) to the plurality of TRPs; and means fortransmitting a measurement report for the plurality of TRPs to a networkentity, wherein the measurement report includes a receive-transmit(Rx-Tx) time difference measurement for at least two TRPs of theplurality of TRPs, and wherein a step size for reporting the Rx-Tx timedifference measurement is based on a time unit T_(c) and one or morenumerology factors.
 16. The UE of claim 15, wherein the Rx-Tx timedifference measurement for each TRP k, where k is an integer, of theplurality of TRPs is defined as T_(UE,Rx,k)−T_(UE,Tx,k) in whichT_(UE,Rx,k) is a time that the UE receives a downlink (DL) radiosubframe from the TRP k, and T_(UE,Tx,k) is a time that the UE transmitsa corresponding uplink (UL) radio subframe to the TRP k.
 17. The UE ofclaim 15, wherein each DL RS is a positioning reference signal (PRS) andthe at least one UL RS is a sounding reference signal (SRS) forpositioning.
 18. The UE of claim 15, wherein a numerology factor of theone or more numerology factors of a TRP k, where k is an integer, of theplurality of TRPs is determined based on at least one of one or morecharacteristics of a DL RS received from the TRP k or one or morecharacteristics of a UL RS transmitted to the TRP k.
 19. The UE of claim15, wherein the measurement report includes, for a TRP k, where k is aninteger, of the plurality of TRPs, an Rx-Tx time difference fieldconfigured to hold an Rx-Tx time difference measurement of the TRP k,and for at least one TRP n, where n is an integer, of the plurality ofTRPs, an Rx-Tx time difference field configured to hold an Rx-Tx timedifference measurement of the TRP n.
 20. The UE of claim 15, wherein themeasurement report includes: a reference Rx-Tx time differencemeasurement; and a differential Rx-Tx time difference measurement. 21.The UE of claim 20, wherein a number of bits for representing thedifferential Rx-Tx time difference measurement is less than a number ofbits for representing the reference Rx-Tx time difference measurement.22. A non-transitory computer-readable medium storingcomputer-executable instructions that, when executed by a user equipment(UE), cause the UE to: receive a plurality of downlink reference signals(DL RSs) from a plurality of transmission reception points (TRPs);transmit at least one uplink reference signal (UL RS) to the pluralityof TRPs; and transmit a measurement report for the plurality of TRPs toa network entity, wherein the measurement report includes areceive-transmit (Rx-Tx) time difference measurement for at least twoTRPs of the plurality of TRPs, and wherein a step size for reporting theRx-Tx time difference measurement is based on a time unit T_(c) and oneor more numerology factors.
 23. The non-transitory computer-readablemedium of claim 22, wherein the Rx-Tx time difference measurement foreach TRP k, where k is an integer, of the plurality of TRPs is definedas T_(UE,Rx,k)−T_(UE,Tx,k) in which T_(UE,Rx,k) is a time that the UEreceives a downlink (DL) radio subframe from the TRP k, and T_(UE,Tx,k)is a time that the UE transmits a corresponding uplink (UL) radiosubframe to the TRP k.
 24. The non-transitory computer-readable mediumof claim 22, wherein each DL RS is a positioning reference signal (PRS)and the at least one UL RS is a sounding reference signal (SRS) forpositioning.
 25. The non-transitory computer-readable medium of claim22, wherein a numerology factor of the one or more numerology factors ofa TRP k, where k is an integer, of the plurality of TRPs is determinedbased on at least one of one or more characteristics of a DL RS receivedfrom the TRP k or one or more characteristics of a UL RS transmitted tothe TRP k.
 26. The non-transitory computer-readable medium of claim 22,wherein the measurement report includes, for a TRP k, where k is aninteger, of the plurality of TRPs, an Rx-Tx time difference fieldconfigured to hold an Rx-Tx time difference measurement of the TRP k,and for at least one TRP n, where n is an integer, of the plurality ofTRPs, an Rx-Tx time difference field configured to hold an Rx-Tx timedifference measurement of the TRP n.
 27. The non-transitorycomputer-readable medium of claim 22, wherein the measurement reportincludes: a reference Rx-Tx time difference measurement; and adifferential Rx-Tx time difference measurement.
 28. The non-transitorycomputer-readable medium of claim 27, wherein a number of bits forrepresenting the differential Rx-Tx time difference measurement is lessthan a number of bits for representing the reference Rx-Tx timedifference measurement.